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Dream Peroxygenases

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A special issue of Antioxidants (ISSN 2076-3921). This special issue belongs to the section "Antioxidant Enzyme Systems".

Deadline for manuscript submissions: closed (10 April 2022) | Viewed by 39333

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Prof. Angel T. Martínez

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Guest Editor

Centro de Investigaciones Biológicas "Margarita Salas" (CIB), CSIC, calle Ramiro de Maeztu 9, E-28040 Madrid, Spain
Interests: enzyme structure-function; heme peroxidases/peroxygenases; flavo oxidases; protein engineering; lignin biodegradation; lignocellulose biorefinery; biocatalysis; enzymatic biotechnology; fungal biotechnology

Prof. Ana Gutiérrez

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Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS), CSIC, Avenida Reina Mercedes 10, E-41012 Seville, Spain
Interests: enzymatic biotechnology; peroxygenases; laccases; oxyfunctionalization reactions; plant lipids; wood chemistry; lignocellulose biorefinery; green chemistry; biocatalysis

Special Issue Information

Dear Colleagues,

Functionally, peroxygenases (EC 1.11.2) are enzymes that catalyze the insertion of an oxygen atom from H₂O₂ into a variety of substrates. They include fungal (e.g., EC 1.11.2.1), animal (e.g., EC 1.11.2.2), plant (e.g., EC 1.11.2.3) and bacterial (such as EC 1.11.2.4 and other cytochrome P450s) enzymes using peroxide as the final electron acceptor and heme as a cofactor.

Among these, the fungal peroxygenases discovered by Prof Martin Hofrichter and coworkers (TU Dresden, Zittau, Germany), and also known as unspecific peroxygenases (UPOs), have emerged as "dream biocatalysts" of the greatest biotechnological interest because they catalyze the oxyfunctionalization of a wide substrate spectrum, often with exquisite regio- and stereo-selectivity. Among the reactions catalyzed by UPOs are the hydroxylation, epoxidation and dealkylation of aromatic and aliphatic compounds, oxidation of organic hetero-atoms and inorganic halides, as well as one-electron oxidation. The substrate diversity of fungal peroxygenases and the product patterns show similarities to P450s and enzymes classified as classical peroxidases, although the above protein families are phylogenetically unrelated.

This Special Issue will collect papers dealing with all aspects of peroxygenases, with a focus on those of the highest biotechnological interest, including genomic screening, heterologous expression, enzyme production, oxygenation reactions, enzyme engineering and process engineering. We aim to provide an updated overview of the state of the art in these enzymes, with papers describing recent developments in structural–functional relationships and optimized syntheses of fine chemicals and pharmaceuticals being especially welcome.

As Guest Editors, we invite you to contribute to the Special Issue on “Dream Peroxygenases”. Original research reports and reviews will be published online in Antioxidants.

Prof. Angel T. Martínez
Prof. Ana Gutiérrez
Guest Editors

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Antioxidants is an international peer-reviewed open access monthly journal published by MDPI.

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Keywords

Heme peroxygenases
Oxyfunctionalization
Regio/stereo-selectivity
Unspecific peroxygenases
Plant peroxygenases
P450 peroxygenases
Green chemistry
Industrial biocatalysis
Pharmaceuticals
Fine chemicals

Published Papers (13 papers)

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21 pages, 2590 KiB

Open AccessArticle

Inhibition of the Peroxygenase Lytic Polysaccharide Monooxygenase by Carboxylic Acids and Amino Acids

by Erik Breslmayr, Peter Poliak, Alen Požgajčić, Roman Schindler, Daniel Kracher, Chris Oostenbrink and Roland Ludwig

Antioxidants 2022, 11(6), 1096; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11061096 - 31 May 2022

Cited by 4 | Viewed by 2000

Abstract

Lytic polysaccharide monooxygenases (LPMOs) are widely distributed in fungi, and catalyze the oxidative degradation of polysaccharides such as cellulose. Despite their name, LPMOs possess a dominant peroxygenase activity that is reflected in high turnover numbers but also causes deactivation. We report on the influence of small molecules and ions on the activity and stability of LPMO during catalysis. Turbidimetric and photometric assays were used to identify LPMO inhibitors and measure their inhibitory effect. Selected inhibitors were employed to study LPMO activity and stability during cellulose depolymerization by HPLC and turbidimetry. It was found that the fungal metabolic products oxalic acid and citric acid strongly reduce LPMO activity, but also protect the enzyme from deactivation. QM calculations showed that the copper atom in the catalytic site could be ligated by bi- or tridentate chelating compounds, which replace two water molecules. MD simulations and QM calculations show that the most likely inhibition pattern is the competition between the inhibitor and reducing agent in the oxidized Cu(II) state. A correlation between the complexation energy and the IC₅₀ values demonstrates that small, bidentate molecules interact strongest with the catalytic site copper and could be used by the fungus as physiological effectors to regulate LPMO activity. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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11 pages, 3004 KiB

Open AccessArticle

Peroxygenase-Catalyzed Selective Synthesis of Calcitriol Starting from Alfacalcidol

by Yuanying Li, Pengpeng Zhang, Zhoutong Sun, Huanhuan Li, Ran Ge, Xiang Sheng and Wuyuan Zhang

Antioxidants 2022, 11(6), 1044; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11061044 - 25 May 2022

Cited by 9 | Viewed by 2443

Abstract

Calcitriol is an active analog of vitamin D3 and has excellent physiological activities in regulating healthy immune function. To synthesize the calcitriol compound, the concept of total synthesis is often adopted, which typically involves multiple steps and results in an overall low yield. Herein, we envisioned an enzymatic approach for the synthesis of calcitriol. Peroxygenase from Agrocybe aegerita (AaeUPO) was used as a catalyst to hydroxylate the C-H bond at the C-25 position of alfacalcidol and yielded the calcitriol in a single step. The enzymatic reaction yielded 80.3% product formation in excellent selectivity, with a turnover number up to 4000. In a semi-preparative scale synthesis, 72% isolated yield was obtained. It was also found that AaeUPO is capable of hydroxylating the C-H bond at the C-1 position of vitamin D3, thereby enabling the calcitriol synthesis directly from vitamin D3. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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16 pages, 4929 KiB

Open AccessArticle

Evolution of Heme Peroxygenases: Ancient Roots and Later Evolved Branches

by Marcel Zámocký and Jana Harichová

Antioxidants 2022, 11(5), 1011; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11051011 - 20 May 2022

Cited by 1 | Viewed by 3633

Abstract

We reconstructed the molecular phylogeny of heme containing peroxygenases that are known as very versatile biocatalysts. These oxidoreductases capable of mainly oxyfunctionalizations constitute the peroxidase–peroxygenase superfamily. Our representative reconstruction revealed a high diversity but also well conserved sequence motifs within rather short protein molecules. Corresponding genes coding for heme thiolate peroxidases with peroxygenase activity were detected only among various lower eukaryotes. Most of them originate in the kingdom of fungi. However, it seems to be obvious that these htp genes are present not only among fungal Dikarya but they are distributed also in the clades of Mucoromycota and Chytridiomycota with deep ancient evolutionary origins. Moreover, there is also a distinct clade formed mainly by phytopathogenic Stramenopiles where even HTP sequences from Amoebozoa can be found. The phylogenetically older heme peroxygenases are mostly intracellular, but the later evolution gave a preference for secretory proteins mainly among pathogenic fungi. We also analyzed the conservation of typical structural features within various resolved clades of peroxygenases. The presented output of our phylogenetic analysis may be useful in the rational design of specifically modified peroxygenases for various future biotech applications. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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14 pages, 1750 KiB

Open AccessArticle

Engineering Collariella virescens Peroxygenase for Epoxides Production from Vegetable Oil

by Dolores Linde, Alejandro González-Benjumea, Carmen Aranda, Juan Carro, Ana Gutiérrez and Angel T. Martínez

Antioxidants 2022, 11(5), 915; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11050915 - 06 May 2022

Cited by 2 | Viewed by 1930

Abstract

Vegetable oils are valuable renewable resources for the production of bio-based chemicals and intermediates, including reactive epoxides of industrial interest. Enzymes are an environmentally friendly alternative to chemical catalysis in oxygenation reactions, epoxidation included, with the added advantage of their potential selectivity. The unspecific peroxygenase of Collariella virescens is only available as a recombinant enzyme (rCviUPO), which is produced in Escherichia coli for protein engineering and analytical-scale optimization of plant lipid oxygenation. Engineering the active site of rCviUPO (by substituting one, two, or up to six residues of its access channel by alanines) improved the epoxidation of individual 18-C unsaturated fatty acids and hydrolyzed sunflower oil. The double mutation at the heme channel (F88A/T158A) enhanced epoxidation of polyunsaturated linoleic and α–linolenic acids, with the desired diepoxides representing > 80% of the products (after 99% substrate conversion). More interestingly, process optimization increased (by 100-fold) the hydrolyzate concentration, with up to 85% epoxidation yield, after 1 h of reaction time with the above double variant. Under these conditions, oleic acid monoepoxide and linoleic acid diepoxide are the main products from the sunflower oil hydrolyzate. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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21 pages, 5663 KiB

Open AccessArticle

Structural Characterization of Two Short Unspecific Peroxygenases: Two Different Dimeric Arrangements

by Dolores Linde, Elena Santillana, Elena Fernández-Fueyo, Alejandro González-Benjumea, Juan Carro, Ana Gutiérrez, Angel T. Martínez and Antonio Romero

Antioxidants 2022, 11(5), 891; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11050891 - 30 Apr 2022

Cited by 7 | Viewed by 3067

Abstract

Unspecific peroxygenases (UPOs) are extracellular fungal enzymes of biotechnological interest as self-sufficient (and more stable) counterparts of cytochrome P450 monooxygenases, the latter being present in most living cells. Expression hosts and structural information are crucial for exploiting UPO diversity (over eight thousand UPO-type genes were identified in sequenced genomes) in target reactions of industrial interest. However, while many thousands of entries in the Protein Data Bank include molecular coordinates of P450 enzymes, only 19 entries correspond to UPO enzymes, and UPO structures from only two species (Agrocybe aegerita and Hypoxylon sp.) have been published to date. In the present study, two UPOs from the basidiomycete Marasmius rotula (rMroUPO) and the ascomycete Collariella virescens (rCviUPO) were crystallized after sequence optimization and Escherichia coli expression as active soluble enzymes. Crystals of rMroUPO and rCviUPO were obtained at sufficiently high resolution (1.45 and 1.95 Å, respectively) and the corresponding structures were solved by molecular replacement. The crystal structures of the two enzymes (and two mutated variants) showed dimeric proteins. Complementary biophysical and molecular biology studies unveiled the diverse structural bases of the dimeric nature of the two enzymes. Intermolecular disulfide bridge and parallel association between two α-helices, among other interactions, were identified at the dimer interfaces. Interestingly, one of the rCviUPO variants incorporated the ability to produce fatty acid diepoxides—reactive compounds with valuable cross-linking capabilities—due to removal of the enzyme C-terminal tail located near the entrance of the heme access channel. In conclusion, different dimeric arrangements could be described in (short) UPO crystal structures. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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10 pages, 2819 KiB

Open AccessArticle

Novel Fatty Acid Chain-Shortening by Fungal Peroxygenases Yielding 2C-Shorter Dicarboxylic Acids

by Andrés Olmedo, René Ullrich, Martin Hofrichter, José C. del Río, Ángel T. Martínez and Ana Gutiérrez

Antioxidants 2022, 11(4), 744; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11040744 - 08 Apr 2022

Cited by 2 | Viewed by 2023

Abstract

Unspecific peroxygenases (UPOs), the extracellular enzymes capable of oxygenating a potpourri of aliphatic and aromatic substrates with a peroxide as co-substrate, come out with a new reaction: carbon-chain shortening during the conversion of fatty acids with the well-known UPOs from Coprinopsis cinerea (rCciUPO) and Cyclocybe (Agrocybe) aegerita (AaeUPO). Although a pathway (Cα-oxidation) for shortening the hydrocarbon chain of saturated fatty acids has already been reported for the UPO from Marasmius rotula (MroUPO), it turned out that rCciUPO and AaeUPO shorten the chain length of both saturated and unsaturated fatty acids in a different way. Thus, the reaction sequence does not necessarily start at the Cα-carbon (adjacent to the carboxyl group), as in the case of MroUPO, but proceeds through the subterminal (ω-1 and ω-2) carbons of the chain via several oxygenations. This new type of shortening leads to the formation of a dicarboxylic fatty acid reduced in size by two carbon atoms in the first step, which can subsequently be further shortened, carbon by carbon, by the UPO Cα-oxidation mechanism. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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12 pages, 7694 KiB

Open AccessArticle

Enzymatic Epoxidation of Long-Chain Terminal Alkenes by Fungal Peroxygenases

by Esteban D. Babot, Carmen Aranda, Jan Kiebist, Katrin Scheibner, René Ullrich, Martin Hofrichter, Angel T. Martínez and Ana Gutiérrez

Antioxidants 2022, 11(3), 522; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11030522 - 08 Mar 2022

Cited by 8 | Viewed by 2701

Abstract

Terminal alkenes are among the most attractive starting materials for the synthesis of epoxides, which are essential and versatile intermediate building blocks for the pharmaceutical, flavoring, and polymer industries. Previous research on alkene epoxidation has focused on the use of several oxidizing agents and/or different enzymes, including cytochrome P450 monooxygenases, as well as microbial whole-cell catalysts that have several drawbacks. Alternatively, we explored the ability of unspecific peroxygenases (UPOs) to selectively epoxidize terminal alkenes. UPOs are attractive biocatalysts because they are robust extracellular enzymes and only require H₂O₂ as cosubstrate. Here, we show how several UPOs, such as those from Cyclocybe (Agrocybe) aegerita (AaeUPO), Marasmius rotula (MroUPO), Coprinopsis cinerea (rCciUPO), Humicola insolens (rHinUPO), and Daldinia caldariorum (rDcaUPO), are able to catalyze the epoxidation of long-chain terminal alkenes (from C_12:1 to C_20:1) after an initial optimization of several reaction parameters (cosolvent, cosubstrate, and pH). In addition to terminal epoxides, alkenols and other hydroxylated derivatives of the alkenes were formed. Although all UPOs were able to convert and epoxidize the alkenes, notable differences were observed between them, with rCciUPO being responsible for the highest substrate turnover and MroUPO being the most selective with respect to terminal epoxidation. The potential of peroxygenases for epoxidizing long-chain terminal alkenes represents an interesting and green alternative to the existing synthesis technologies. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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15 pages, 2266 KiB

Open AccessArticle

Cell-Free Protein Synthesis with Fungal Lysates for the Rapid Production of Unspecific Peroxygenases

by Marina Schramm, Stephanie Friedrich, Kai-Uwe Schmidtke, Jan Kiebist, Paul Panzer, Harald Kellner, René Ullrich, Martin Hofrichter and Katrin Scheibner

Antioxidants 2022, 11(2), 284; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11020284 - 30 Jan 2022

Cited by 3 | Viewed by 3460

Abstract

Unspecific peroxygenases (UPOs, EC 1.11.2.1) are fungal biocatalysts that have attracted considerable interest for application in chemical syntheses due to their ability to selectively incorporate peroxide-oxygen into non-activated hydrocarbons. However, the number of available and characterized UPOs is limited, as it is difficult to produce these enzymes in homologous or hetero-logous expression systems. In the present study, we introduce a third approach for the expression of UPOs: cell-free protein synthesis using lysates from filamentous fungi. Biomass of Neurospora crassa and Aspergillus niger, respectively, was lysed by French press and tested for translational activity with a luciferase reporter enzyme. The upo1 gene from Cyclocybe (Agrocybe) aegerita (encoding the main peroxygenase, AaeUPO) was cell-free expressed with both lysates, reaching activities of up to 105 U L⁻¹ within 24 h (measured with veratryl alcohol as substrate). The cell-free expressed enzyme (cfAaeUPO) was successfully tested in a substrate screening that included prototypical UPO substrates, as well as several pharmaceuticals. The determined activities and catalytic performance were comparable to that of the wild-type enzyme (wtAaeUPO). The results presented here suggest that cell-free expression could become a valuable tool to gain easier access to the immense pool of putative UPO genes and to expand the spectrum of these sought-after biocatalysts. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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16 pages, 6977 KiB

Open AccessArticle

Broadening the Biocatalytic Toolbox—Screening and Expression of New Unspecific Peroxygenases

by Sebastian Bormann, Harald Kellner, Johanna Hermes, Robert Herzog, René Ullrich, Christiane Liers, Roland Ulber, Martin Hofrichter and Dirk Holtmann

Antioxidants 2022, 11(2), 223; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11020223 - 24 Jan 2022

Cited by 11 | Viewed by 3658

Abstract

Unspecific peroxygenases (UPOs) catalyze the selective transfer of single oxygen atoms from peroxides to a broad range of substrates such as un-activated hydrocarbons. Since specific oxyfunctionalizations are among the most-desired reactions in synthetic chemistry, UPOs are of high industrial interest. To broaden the number of available enzymes, computational and experimental methods were combined in this study. After a comparative alignment and homology modelling, the enzymes were expressed directly in P. pastoris. Out of ten initially selected sequences, three enzymes (one from Aspergillus niger and two from Candolleomyces aberdarensis) were actively expressed. Cultivation of respective expression clones in a bioreactor led to production titers of up to 300 mg L⁻¹. Enzymes were purified to near homogeneity and characterized regarding their specific activities and pH-optima for typical UPO substrates. This work demonstrated that directed evolution is not necessarily required to produce UPOs in P. pastoris at respective titers. The heterologous producibility of these three UPOs will expand the toolbox of available enzymes and help to advance their synthetic application. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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17 pages, 3918 KiB

Open AccessArticle

Regioselective and Stereoselective Epoxidation of n-3 and n-6 Fatty Acids by Fungal Peroxygenases

by Alejandro González-Benjumea, Dolores Linde, Juan Carro, René Ullrich, Martin Hofrichter, Angel T. Martínez and Ana Gutiérrez

Antioxidants 2021, 10(12), 1888; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10121888 - 25 Nov 2021

Cited by 8 | Viewed by 2364

Abstract

Epoxide metabolites from n-3 and n-6 polyunsaturated fatty acids arouse interest thanks to their physiological and pharmacological activities. Their chemical synthesis has significant drawbacks, and enzymes emerge as an alternative with potentially higher selectivity and greener nature. Conversion of eleven eicosanoid, docosanoid, and other n-3/n-6 fatty acids into mono-epoxides by fungal unspecific peroxygenases (UPOs) is investigated, with emphasis on the Agrocybe aegerita (AaeUPO) and Collariella virescens (rCviUPO) enzymes. GC-MS revealed the strict regioselectivity of the n-3 and n-6 reactions with AaeUPO and rCviUPO, respectively, yielding 91%-quantitative conversion into mono-epoxides at the last double bond. Then, six of these mono-epoxides were obtained at mg-scale, purified and further structurally characterized by ¹H, ¹³C and HMBC NMR. Moreover, chiral HPLC showed that the n-3 epoxides were also formed (by AaeUPO) with total S/R enantioselectivity (ee > 99%) while the n-6 epoxides (from rCviUPO reactions) were formed in nearly racemic mixtures. The high regio- and enantioselectivity of several of these reactions unveils the synthetic utility of fungal peroxygenases in fatty acid epoxidation. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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11 pages, 1369 KiB

Open AccessArticle

Stereospecific Epoxidation of Limonene Catalyzed by Peroxygenase from Oat Seeds

by Daniela Maria Biondi, Claudia Sanfilippo and Angela Patti

Antioxidants 2021, 10(9), 1462; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox10091462 - 14 Sep 2021

Cited by 6 | Viewed by 2252

Abstract

Limonene is one of the most abundant naturally occurring cyclic monoterpenes and has recently emerged as a sustainable alternative to petroleum-based solvents as well as a chemical platform for the production of value-added compounds. The biocatalytic epoxidation of both enantiomers of limonene was carried out in the presence of a peroxygenase-containing preparation from oat (Avena sativa) flour. Different reaction profiles were observed depending on the starting enantiomer of limonene, but in both cases the 1,2-monoepoxide was obtained as the main product with excellent diastereoselectivity. Trans-1,2-monoepoxide and cis-1,2-monoepoxide were isolated from the reaction of (R)-limonene and (S)-limonene, respectively, and the reactions were scaled-up to 0.17 M substrate concentration. The process is valuable for operational simplicity, lack of toxic metal catalysts, and cost-effectiveness of the enzymatic source. Pure stereoisomers of 1,2-monoepoxides of limonene constitute a useful starting material for biorenewable polymers, but can be also converted into other chiral derivatives by epoxide ring opening with nucleophiles. As a proof of concept, a tandem protocol for the preparation of enantiopure (1S,2S,4R)-1,2-diol from (R)-limonene and (1R,2R,4S)-1,2-diol from (S)-limonene was developed. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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Review

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17 pages, 2682 KiB

Open AccessReview

A Unique P450 Peroxygenase System Facilitated by a Dual-Functional Small Molecule: Concept, Application, and Perspective

by Siyu Di, Shengxian Fan, Fengjie Jiang and Zhiqi Cong

Antioxidants 2022, 11(3), 529; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11030529 - 10 Mar 2022

Cited by 10 | Viewed by 3001

Abstract

Cytochrome P450 monooxygenases (P450s) are promising versatile oxidative biocatalysts. However, the practical use of P450s in vitro is limited by their dependence on the co-enzyme NAD(P)H and the complex electron transport system. Using H₂O₂ simplifies the catalytic cycle of P450s; however, most P450s are inactive in the presence of H₂O₂. By mimicking the molecular structure and catalytic mechanism of natural peroxygenases and peroxidases, an artificial P450 peroxygenase system has been designed with the assistance of a dual-functional small molecule (DFSM). DFSMs, such as N-(ω-imidazolyl fatty acyl)-l-amino acids, use an acyl amino acid as an anchoring group to bind the enzyme, and the imidazolyl group at the other end functions as a general acid-base catalyst in the activation of H₂O₂. In combination with protein engineering, the DFSM-facilitated P450 peroxygenase system has been used in various oxidation reactions of non-native substrates, such as alkene epoxidation, thioanisole sulfoxidation, and alkanes and aromatic hydroxylation, which showed unique activities and selectivity. Moreover, the DFSM-facilitated P450 peroxygenase system can switch to the peroxidase mode by mechanism-guided protein engineering. In this short review, the design, mechanism, evolution, application, and perspective of these novel non-natural P450 peroxygenases for the oxidation of non-native substrates are discussed. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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21 pages, 4962 KiB

Open AccessEditor’s ChoiceReview

Peroxide-Mediated Oxygenation of Organic Compounds by Fungal Peroxygenases

by Martin Hofrichter, Harald Kellner, Robert Herzog, Alexander Karich, Jan Kiebist, Katrin Scheibner and René Ullrich

Antioxidants 2022, 11(1), 163; https://0-doi-org.brum.beds.ac.uk/10.3390/antiox11010163 - 14 Jan 2022

Cited by 27 | Viewed by 4818

Abstract

Unspecific peroxygenases (UPOs), whose sequences can be found in the genomes of thousands of filamentous fungi, many yeasts and certain fungus-like protists, are fascinating biocatalysts that transfer peroxide-borne oxygen (from H₂O₂ or R-OOH) with high efficiency to a wide range of organic substrates, including less or unactivated carbons and heteroatoms. A twice-proline-flanked cysteine (PCP motif) typically ligates the heme that forms the heart of the active site of UPOs and enables various types of relevant oxygenation reactions (hydroxylation, epoxidation, subsequent dealkylations, deacylation, or aromatization) together with less specific one-electron oxidations (e.g., phenoxy radical formation). In consequence, the substrate portfolio of a UPO enzyme always combines prototypical monooxygenase and peroxidase activities. Here, we briefly review nearly 20 years of peroxygenase research, considering basic mechanistic, molecular, phylogenetic, and biotechnological aspects. Full article

(This article belongs to the Special Issue Dream Peroxygenases)

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